Q.Gardenia Plant Leaves Are Not Dark Green
I have two gardenia plants in pots, one is terrific and the other has leaves that are not a dark green. I recently repotted the sickly one and it does have new growth, but the leaves are just not turning green. I did fertilize and noted that some of the new growth ends are slightly brown.

Certified GKH Gardening Expert
It sounds like it may have chlorosis. This article will help you with that:
https://www.gardeningknowhow.com/plant-problems/environmental/leaf-chlorosis-and-iron.htm